U.S. jets blasted Taliban strongholds on Afghanistan's two main battle fronts Saturday, and the opposition northern alliance chose its representatives to negotiate with other Afghan factions to create a broad-based government to replace the Taliban.

The Pentagon, meanwhile, confirmed it lost an unmanned Predator spy plane over Afghanistan – but insisted it was due to bad weather, not Taliban fire. It denied Taliban claims to have shot down two U.S. aircraft.

At both fronts, opposition leaders praised the U.S. air strikes, saying they were weakening Taliban defenses – after days of complaining that the attacks were too weak to dislodge the Islamic militia. U.S. planes began attacking targets along the Kabul front before dawn Saturday and continued into the day, hitting Taliban tanks and a Taliban hilltop headquarters overlooking the Shomali plain about 30 miles north of Kabul, according to the opposition.

Along Afghanistan's other main front – Mazar-e-Sharif – opposition spokesman Ashraf Nadeem said U.S. jets staged "continuous bombing" attacks Saturday against Taliban positions in Samangan province about 40 miles east of the strategic northern city.

Opposition forces claimed to have seized an outlying district along the Mazar-e-Sharif front in heavy fighting as they pressed toward the city itself. The claim could not be independently verified.

Capturing Mazar-e-Sharif would cut Taliban supply lines to the west and enable the opposition to bring in weapons and equipment from Tajikistan and Uzbekistan.

"We are happy. It is very effective," Bismillah Khan, an opposition commander coordinating anti-Taliban forces at two provinces near the Kabul front, said of the U.S. strikes.

Mir Rahman, deputy brigade commander at the front-line Bagram district north of Kabul, said Saturday the air strikes have "weakened the Taliban," taking out 40 artillery pieces and 10 tanks in the past week.

Another opposition commander, Abdul Rahman, said intercepts of Taliban radio messages indicated the Islamic militia had brought up 600 new Arab and Pakistani reinforcements to bolster their positions near the Kabul front.

President Bush launched the air assault Oct. 7 after the Taliban refused to hand over Osama bin Laden, chief suspect in the Sept. 11 terrorist attacks on the World Trade Center and the Pentagon, which killed about 4,500 people.

Despite the attacks, Taliban Information Minister Qadratullah Jamal insisted Taliban morale remains high. "Even if a Taliban dies, his friend is behind him running forward. He is not afraid to lose his life. He knows he will go to heaven," Jamal told The Associated Press.

The intensification of American strikes of the front lines raise the possibility that alliance forces could move on Kabul before a broad-based coalition of Afghan factions can be built to replace the Taliban regime – a possible recipe for instability in this ethnically complex country.

But a top northern alliance politician insisted Saturday that political efforts were keeping pace with the military action, saying the alliance had picked its representatives to negotiate with other factions – a step toward forming the coalition.

"All of Afghanistan's ethnic groups will be represented" in a post-Taliban government, said the politician, Saeed Hussein Anwari. He said the alliance had picked 60 representatives to meet with the same number of representatives from Afghanistan's former king, Mohammed Zaher Shah, at a gathering in Turkey planned to take place in the coming days.

That meeting would work toward establishing a Grand Council, or Loya Jirga, to appoint an interim government once the Taliban fall.

Pakistan and others in the U.S.-led campaign against terrorism doubt the northern alliance – which is dominated by Afghanistan's minority ethnic Tajiks and Uzbeks – can win broad approval among the country's dominant Pashtun ethnic group. Also, there are worries about the opposition's ability to rule, since when its leaders held power five years ago, they plunged the country into a blood bath of factional infighting that killed thousands.

The United States and its allies hope the presence of the exiled former king, Zaher Shah, in negotiations for the Loya Jirga, can bring Pashtun tribes from the south into a new government.

In Washington, Pentagon spokesman Air Force Maj. Mike Halbig denied Taliban claims that they had shot down two U.S. aircraft and killed dozens of Americans.

"It's false. As many claims with the Taliban, it is simply not true," he said.

A U.S. helicopter crashed Friday in Afghanistan while trying to pick up a sick soldier, and its crew themselves had to be rescued by another helicopter, the Pentagon said. All four helicopter crew members survived with non-life-threatening injuries, Washington said.

The Pentagon blamed bad weather – that part of Afghanistan has seen days of freezing rain and fog – for that crash and loss of the unmanned spy plane.

In other developments:

– Pakistani President Pervez Musharraf urged "very serious consideration" to suspending the U.S. bombing campaign during the Muslim holy month.

– The Taliban released a French journalist arrested last month after illegally entering Afghanistan, handing him over to French diplomats at the border with Pakistan.

– Qatar's al-Jazeera station broadcast a video featuring Osama bin Laden condemning any Arab leaders who turn to the United Nations for peace negotiations. "They are infidels," he said. It was unclear when the tape was made.